The invention concerns a clamp for connecting a cylindrical temperature sensor axis-parallel to a tube with co-engagement of the temperature sensor and the tube, the clamp having a bendable metal tension band, which band has a first jaw at a first end section, a second jaw shapewise connectable with a second end section of the tension band, and which clamp also includes a tension screw, wherein the tension screw extends through a bore in the first jaw and is threaded through a threaded bore in the second jaw.
In a known clamp of this type (U.S. Pat. No. 2,863,203) the second jaw has a plate shaped nut. The second end section of the tension band is provided with a plurality of hole pairs spaced from one another in the longitudinal direction of the tension band. The nut has two bosses which can be received in a hole pair suiting the diameters of the involved temperature sensor and tube, and accordingly corresponding to the required effective length of the tension band, to shapewise connect the tension band with the nut. Additionally, a longitudinal slot is formed in the tension band through which the tension screw can be inserted. The holes as well as the slot in the tension band create a weakening of the tension band. Therefore, the tension force exertable by the tension band is limited and relatively low. In many cases only a linear engagement between the temperature sensor and the tube is possible, and as a rule even only a point contact is possible since the tube and/or the sensor housing often in transport or because of uncareful handling is so deformed that they are no longer both of cylindrical shape. Therefore, the heat transfer resistance between the temperature sensor and the tube is relatively high.
The invention has as its object the provision of a clamp of the above-mentioned kind which makes possible the exertion of a high-tension force and which thereby makes possible the achievement of a low heat transfer resistance between the tube and the temperature sensor.
In accordance with the invention, this object is achieved in that the second jaw has a bent plate with a first leg and with a second leg perpendicular to the first leg, that the first leg is provided with a threaded bore and the second leg with a slot for passage therethrough of the second end section of the tension band, that the length of the tension band is so chosen that the second end section after the wrapping of the tension band around the temperature sensor and the tube as well as after its passage through the slot is bendable down onto the second leg, and that the length of the tension screw is so chosen that after its tightening it lies on the bent down second end section.
With this solution, the need for providing a slot in the tension band and of holes in its second end section is avoided. At least one of the two parts to be connected can thereby be at least so far deformed that a surface area engagement between the temperature sensor and the tube is achieved. Accordingly, a low heat transfer resistance between the two parts can be obtained.
Preferably, the first jaw has a plate which contains the bore, around which plate a first end section is bent so that it lies against both faces of the plate, and that the first end section on both sides of the plate is provided with a hole, with the hole being aligned with the bore. While in the known clamp a first jaw is formed by the bending of the end section onto itself and by the forming of two holes aligned with one another in the tension band for receiving the tension screw, so that the holes are subjected to a high hole bearing pressure by the shaft of the tension screw and as a result become enlarged or even torn, in the case of the construction according to the invention the first jaw is in the form of a plate surrounded by the first end section of the tension band and takes on the main load upon tightening. The wrapping of the end section around at least two edges of the plate in itself already provides a very secure shapewise connection. The holes in the end section are thus loaded to only a small degree. By these measures all together a yet higher load capacity of the clamp is obtained.
The tension band can moreover be made of copper which has a high heat conductivity and is also significantly corrosion resistant.
Then the first leg which is bent nearly or substantially perpendicularly to the second jaw can have a bushing which lengthens its threaded bore. The second jaw can, therefore, be made to be relatively thin with the threads of the threaded bore nevertheless being able to carry a high load.
Further, the second leg can have a step in the form of a two-stage bend between the first leg and the slot, which step in reference to the inner side of the tension band extends outwardly by an amount which corresponds to the thickness of the tension band. The jaw can therefore in the area between the first leg and the slot be supported by the corresponding portion of the part to be connected. Thereby, a danger of a bending of the first leg is diminished.
Still further, it can be provided that the threaded shank of the tension screw has a thread free neck and that the bore in the first jaw is provided with threads. The tension screw is then secured at its thread free neck by the surrounding threaded bore of the first jaw in its installed position in the jaw before the assembly of the clamp.
If the tension screw has a cutting thread, it itself can cut the thread in the threaded bore.